Apparatus employed in wireles telegraphy.



No. 650,||U. Patented May 22, I900. G. MARCONI.

APPABATUSENIPLOYED'IN WIRELESS TELEGRAPHY.'

, (Application filed Dec. 28, 1899.)

(No Model.)

R 1 R I l I UNITED STATES PATENT OFFICE.

GUGLIELMO MARCON I, OF LONDON, ENGLAND, ASSIGNOR TO THE WIRELESS TELEGRAPH AND SIGNAL COMPANY, LIMITED, OF SAME'PLACE.

APPARATUS EMPLOYED IN WIRE LESS'TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 650,110, dated May 22, 1900.

Application filed December 28, 1899. Serial No. 741,820. (No model.)

To all whom it may concern:

Be it known that I, GUGLIELMO MARcom, electrician, a subject of the King of Italy, residing at 28 Mark Lane, in the city of London, England, have invented certain new and useful Apparatus Employed in Wireless Telegraphy, of which the following is a specification.

In the specification of a former patent, dated the 13th day of July, 1897, No. 586,193, an arrangement is described in which the transmitter consisted of a sparking appliance having one terminal connected to an insulated condoctor in the air and the other terminal to earth,while the receiver contained asensitive tube or sensitive imperfect contact having one end connected to a similar conductor and the other end to earth. It is found that the aerial conductor sometimes becomes charged with atmospheric electricity, and when the same qonductor is used both for transmitting and receiving this electricity discharges through the operator when he shifts the conductor from the transmitter to the receiver or through the imperfect contact'when the conductor is shifted from one instrument to the other, and this is liable to give a shock to the operator or to injure the imperfect contact.

The object of this invention is to remove this inconvenience and also to render it impossible for the operator to accidentally opcrate his transmitter, and thereby cause a spark when the aerial conductor at his. station is connected to the rece'iver,which might injure the imperfect contact.

According to this invention the aerial conductor is led in close proximity to one terminal of the sparking appliance, and therefore if a Rluhmkorff coil or transformer is used the aerial conductor can discharge itself through the small spark-gap to earth through the secondary winding, thus preventing the accumulation of atmospheric electricity in it. The signals are sent as before, by means of a Morse key in a local-battery circuit, through the primary of the Ruhmkortf coil or transformer.

According to this invention the arm of the key is prolonged beyond its pivot and carries an insulated terminal, which is permanently of the induction-coil 0.

connected to the aerial conductor. Below this terminal there is on the base of the instrument the terminal of the receiver. The arm is so arranged that immediately it is released by the operator after sending a message it turns about on its pivot, bringing the above-mentioned conductors together, thus connecting the receiver to the aerial conductor.

The drawing is a diagram of acombined transmitting and receiving station arranged in accordance with this invention.

The letters, so far as they are applicable, are the same as those employed in the former specification.

a is a battery, and b an ordinary Morse key closing the circuit through the primary of a Ruhmkorfi coil 0, the terminals of the secondary being connected to metallic balls e.

The aerial conductor u is led in close proximity to, say, within one centimeter of one of the balls e, the other being connected to earth E. The key I) has two contacts Z) W, insulated from each other. The diagram shows the key in the position for sending, the contact b touching the contact 11 and closing the circuit of the battery (1 through the primary Immediately the key is released by the operator its longer arm falls by its own weight, the contact I) descending onto the contact b which is connected to the receiver R by the wire M. The receiver R is inclosed in abox R of conducting material and may be such and so connected as is described in my former United States patent, No. 624,516. The invention can also be applied to receivers, as described in the specification of the patent dated the 13th day of July, 1897, No. 586,193. The means adopted for protecting the receiver are preferably those described in the specification of the patent dated the 27th day of June, 1899, No. 627,650. The wire connecting the receiver to the terminal on the base of the key should preferably be inclosed in a metal tube N to protect it from the oscillations of the local transmitter, and the tube N should be electrically connected to the box R.

' This invention is also applicable if the earth connection is substituted by a capacity area.

In this case the capacities of the transmitter and receiver should preferably be connected together.

What I claim is- 1. The combination of the primary and-secondaryof a sparking appliance, a battery and key in circuit with the primary, an aerialconductor led in close proximity to one terminal of the secondary, means for connecting the said aerial conductor to the receiving instrument', and a capacity connected to the other terminal.

2. The combination of the primary and secondary of a sparking appliance, a battery and key in circuit with the primary, an aerial conductor led in close proximity to one terminal of the secondary, means for connecting the said aerial conductor to the receiving instrument, and an earth connection connected to the other terminal.

31 The combination of the primary'and secondary of a sparking appliance, a battery in circuit with-the primary, an aerial conductor led in close proximity to one terminal of the secondary, a capacity connected to the other terminal, a receiver, two fixed contacts one onda'ry of a sparking appliance, a battery in circuit with the primary, an aerial conductor led'in close proximity to one terminal of the secondary, an earth connection connected to the other terminal, a receiver, two fixed contacts one connected to'one terminal of the primary and the other to the receiver, a pivoted arm and two contacts on the arm insulated from each other and opposite the fixed contacts one being connected to the other terminal of the primary and the other to the aerial conductor.

GUGLIELMO MARCONI.

Witnesses:

HENRY W. ALLEN,- GEo. J F ANKLIN, 

